Schümperli D, McKenney K, Sobieski D A, Rosenberg M
Cell. 1982 Oct;30(3):865-71. doi: 10.1016/0092-8674(82)90291-4.
Precise frameshift and nonsense mutations were introduced into the region preceding the galactokinase gene (galK) of Escherichia coli. These mutations after the position at which upstream translation terminates relative to the galK translation initiation signal. Constructions were characterized that allow ribosomes to stop selectively before, within or downstream from the galK initiation signal. The effects of these mutations on galK expression were monitored. Galactokinase levels are highest when upstream translation terminates within the galK initiation region. In contrast, when translation stops either upstream or down stream from the galK start site, galK expression is drastically reduced. These results demonstrate that the galK gene is translationally coupled to the gene immediately preceding galK in the gal operon (that is, galT), and that the coupling effect depends primarily on the position at which upstream translation terminates relative to the galK start site. Possible mechanisms and implications of this translational coupling phenomenon are discussed.
精确的移码突变和无义突变被引入到大肠杆菌半乳糖激酶基因（galK）之前的区域。这些突变发生在相对于galK翻译起始信号上游翻译终止的位置之后。构建了一些结构，使核糖体能够在galK起始信号之前、之内或下游选择性地停止。监测了这些突变对galK表达的影响。当上游翻译在galK起始区域内终止时，半乳糖激酶水平最高。相反，当翻译在galK起始位点上游或下游停止时，galK表达会急剧降低。这些结果表明，galK基因在翻译上与gal操纵子中紧接在galK之前的基因（即galT）偶联，并且这种偶联效应主要取决于上游翻译相对于galK起始位点终止的位置。讨论了这种翻译偶联现象的可能机制及其意义。
